Adjust homepage markup and CSS to fix validation and wdn overrides

The input group should not be used with grid CSS. The font sizes and
padding should not be manually adjusted. The input label should be
outside the input group and should not be hidden during field
interaction.
Remove media styles affecting search
Make CSS for MediaList media consisten on all views
Fix validation errors in media teaser
Merge pull request #154 from unl/homepage-cleanup

Homepage cleanup